While a portable electronic device is generally diversified in its function, a more portable device has more competitive power. For example, even with the same function, a slimmer, lighter, and simpler portable electronic device is preferred. Accordingly, portable electronic device manufacturers are developing slimmer, lighter, and simpler electronic devices than other projects, with the same or better performance.
Following this trend, electronic devices are miniaturized and their cost is rising. Consumers who purchase the high-priced electronic device put the electronic device in a separate protective cover in order to protect an exterior of the electronic device and to maximize the grip. The protective cover is formed of a material which can be attached to one side of the electronic device or can cover the whole device excluding a display device.
However, such a protective cover merely protects the electronic device or decorates the exterior, and more functions are nonexistent.